Short communicationDietary administration of tetrodotoxin and its putative biosynthetic intermediates to the captive-reared non-toxic Japanese fire-bellied newt, Cynops pyrrhogaster

•Tetrodotoxin (TTX) and its related compounds were dietary administered to the newt.•TTX was detected mainly in the body of the newt 4 weeks after administration.•TTX and its related compounds in the tested newt were hardly secreted for 4 weeks.•Administered compounds were not converted into other analogues in the newt.

The origin of tetrodotoxin (TTX) in amphibians has long been disputed. In this study, TTX and its putative biosynthetic intermediates or shunt compounds (4,9-anhydro-10-hemiketal-5-deoxyTTX and Cep-242) were dietary administered to the captive-reared, non-toxic Japanese fire-bellied newt, Cynops pyrrhogaster. After 4 weeks, the ingested compounds were detected mainly in the newt body using liquid chromatography-mass spectrometry (LC-MS), while these compounds were not converted into other TTX analogues in newts.